The present invention is an improvement over prior cantilever-type gate assemblies principally by reason of the fact that it is more economical to assemble and install, is safer and may be adapted readily to a gate comprised of conventional pipe tubing welded in a rectangular configuration and having conventional chain link fencing covering the opening in the frame. In accordance with a prior known cantilever gate assembly, the gate assembly is supported for transverse movement between an open and closed position between upper and lower rollers supported on fence posts adjacent the gate opening. While these systems are generally simple and economical they present certain disadvantages and drawbacks. For example, since the rollers are exposed to the elements, it has been found that snow and ice which may accumulate on the rollers causes freezing or jamming of the gate assembly. Furthermore, exposed rollers present a safety hazard to humans particularly children who may playfully hang from a horizontal support of the gate and ride the gate back and forth and in this process have their hands jammed between the horizontal frame members and the support rollers.
These prior roller supported gate assemblies include essentially four spaced rollers, two upper rollers which engage the top rail of the gate assembly and two spaced lower rollers which engage the bottom rail. In this type of gate mounting, the amount of sag depends on the precise geometry of the gate frame. Thus, if the gate frame is out of line or if there is too much clearance, large sag results when the gate is at opposite closed or open limit positions. On the other hand, if the sliding fit between the rollers and the upper and lower frame members of the gate is too tight, the gate binds and is extremely difficult to actuate and in some instances may bind to a point where it will jam or lock.
In these prior roller support systems, it has been found that it is necessary to make the gate frame of a heavy sturdy construction to minimize compression or crushing effects between the gate and roller when it is in its fully cantilevered open or closed position.
Furthermore, it has been found that these gate assemblies are generally cumbersome and difficult to operate and exhibit a large amount of sag particularly in gates for large openings often necessitating support or guide means in the form of rollers which engage the surface in the gate opening to help support the weight of the gate.
Another prior cantilever-type gate assembly is shown in Ashworth U.S. Pat. No. 3,705,468 issued Dec. 12, 1972. This assembly is rather sophisticated and hence costly to manufacture and install. Furthermore, the trackway opens upwardly and, therefore, is exposed to ingress of foreign matter such as dirt which may jam the operation. Additionally, this construction does not foreclose accumulation of snow in the channel which likewise could affect normal operation of the gate system.
Another prior sliding gate assembly is shown in the Case U.S. Pat. No. 3,394,497. This system is a vertical system and incorporates pulleys in a rather complicated and complex trackway system requiring a special gate construction. This system is not adapted to simple pipe-type gate assembly for which the present invention is particularly adapted. Furthermore, the cooperating mechanisms are exposed to the environment thereby presenting the problems noted above in inclement weather in connection with the Ashworth Patent.